Updated Gear Review, Winter Bivy Quest, Vapor Barrier Layers

Bikepacking the fields of EnglandI put up a video review yesterday of the Porcelain Rocket frame bags.  Scott hand builds these up in Canada and they are top notch products. I am a huge fan of going ultra-light on a bike, and in so doing, you really need a set of these bags to help simplify your travels.  If you don't have the time or inclination to go custom, then Salsa now has a line of bags that they are creating in partnership with Revelate. These bags are currently designed for the Salsa Mukluk, although early 2012 they will have bags available for both the Fargo and the Spearfish.  Another option if Scott is too backed up is to check with Revelate and see what Eric's stock is like.  All three are great options.

Winter Bivy Selection

Because I have decided to spend a considerable amount of time this winter in sub-freezing temperatures, I continue to search for a viable winter bivy bag.  I am definitely looking for a sub 500g bag that is sized for cold weather bags and pads.  If you have any advice or suggestions please drop me a note or post here.  Right now I am leaning towards one of these bags:

• Integral Designs Micro Bivy
• MLD Soul Bivy
• Alpkit Hunka
• PHD Winter Bivy

Your advice and/or suggestions are greatly appreciated. 

Vapor Barrier Layers - VBL

Lastly, as part of my sub-zero kit, I will be layering slightly different than what you would normally do in temperatures above freezing.  The concept is relatively new, and is built around the use of Vapor Barrier Layers (VBL).  The concept in short is that instead of using a breathable layer next to your skin, you want to instead use a non-breathable layer that allows the body to keep a warm and damp micro-climate on your skin.  Apparently by doing this you get two major benefits. 

The first is that since you are not wicking away moisture, you allow your body to more accurately regulate the amount of sweat produced.  Apparently if you are constantly sweating and wicking the body just keeps sweating.  However, if you can keep a warmer layer next to the skin, your body does a much better job of regulating this climate.  This is why during the winter we pump water into our heating systems and during the summer we suck it out.  RBH Designs has a great FAQ section which talks specifically about the use of their products but also contains some generic information regarding the use of a VBL.  I will post more links to research papers that I have been reading which will do a much better job of explaining this than I can.  

The other major benefit is that in a sub-freezing environment the dew point sits between your base layers and your insulation layers.  So if you are wearing breathable, wicking fabrics next to your insulation layer, you will have moisture coming off of your body, turning into condensation within your insulation layer.  This has the effect of diminishing the effectiveness of the insulation layer, and with your sleeping bag, it will freeze once you are out of the bag.   There have been reports of expeditioners who's sleeping bags have gained pounds of frozen moisture during the course of longer trips.

I will be experimenting with several different types of VBL's including the use of Reed's Chillcheater Aquatherm fabrics.  This idea came to me as I was packing up my kayak kit and I realized that the Chillcheater product is actually a VBL.  It is waterproof/windproof with a thin fleece liner.  Reed makes some lighter weight products which may very well work perfectly.  There is also a company called RBH which has made a name for itself with their patented VBL shirts, gloves, and pants.  Lastly there are several companies that make VBL liners for your sleeping bag, but this is overkill if you are already wearing a VBL.

Stay tuned for more details and my findings as I begin training for my cold weather activities.